Hello, I currrently own a 2005 infiniti coupe with 78k miles stock. I have lately heard a rattling noise from the engine bay every tine I start it in the morning. It eventually disappeares but lately it has taken more time then usual. I want to know if anyone else has had this problem before and please give me some advice.

Timing chain rattle is my guess, if it's in fact coming from the engine bay. Otherwise a common culprit is cat heat shields.

Ok thanjs and if in case it were to be the timimng chain how hard would that be and how expensiive ? Thanj you

Easiest thing to check is the left black cover pops off. There is a small plunger in there and if it's all the way out you need a new guide rail. If it is indeed that it's at least a grand in labor to fix. That just keeps tension until enough oil pressure builds up.